A region of a eukaryotic chromosome is heavily transcribed by RNA polymerase II. Given below are a few properties of such a chromatin.

A. DNaseI hypersensitivity
B. High CpG methylation
C. Occupied by macroH2A
D. High histone acetylation

Choose the option that has all correct properties.

Correct option is D

Let's analyze the properties related to a region of chromatin that is heavily transcribed by RNA polymerase II:

1. DNaseI Hypersensitivity (A):

   • Correct. Active regions of chromatin that are transcribed by RNA polymerase II tend to be hypersensitive to DNase I, meaning they are more easily digested by DNase I. This occurs because these regions are loosely packed (euchromatin), allowing the enzyme to access the DNA more readily.

2. High CpG Methylation (B):

   • Incorrect. High CpG methylation is typically associated with gene silencing, not transcription. When the CpG islands in promoter regions are heavily methylated, it prevents transcription, which is the opposite of what happens in heavily transcribed regions.

3. Occupied by MacroH2A (C):

   • Incorrect.MacroH2A is a variant of the histone H2A, which is generally associated with inactive chromatin (heterochromatin), not with active transcription. Heavily transcribed regions are not typically associated with macroH2A, which is involved in gene silencing.

4. High Histone Acetylation (D):

   • Correct. High histone acetylation is a hallmark of active transcription. Acetylation of histones relaxes the chromatin structure, allowing RNA polymerase II to access the DNA and transcribe the genes. This is commonly observed in euchromatin.

The correct answer is Option 4: A and D only, as DNaseI hypersensitivity (A) and high histone acetylation (D) are associated with heavily transcribed chromatin regions.